How to see kernel pr_err error messages.

How to see kernel pr_err error messages.

[reg]

Im looking at some kernel code, and there are 'pr_err' error messages in
it that would help me discover my problem.

However I dont see them printing anywhere.

What do I have to do to see these error messages?
A search with GOOGLE  and a grep of the code wasnt too useful, but
it seems possible that I need to set

    #define CONFIG_DEBUG

Is that true?  I see a lot of <something>_DEBUGs in the .config file
but no simple CONFIG_DEBUG that is commented out.

In any case, how do I get these things to print?
-- 
                                        Reg.Clemens
                                        reg@dwf.com

Re: How to see kernel pr_err error messages.

[Borislav Petkov]

From: reg@dwf.com
Date: Sat, Feb 27, 2010 at 03:11:03AM -0700

> Im looking at some kernel code, and there are 'pr_err' error messages in
> it that would help me discover my problem.
> 
> However I dont see them printing anywhere.
> 
> What do I have to do to see these error messages?

Take a look at 'ignore_loglevel' and 'loglevel' kernel parameters in
<Documentation/kernel-parameters.txt> depending on what exactly you want
to achieve.

> A search with GOOGLE  and a grep of the code wasnt too useful, but
> it seems possible that I need to set
> 
>     #define CONFIG_DEBUG
> 
> Is that true?  I see a lot of <something>_DEBUGs in the .config file
> but no simple CONFIG_DEBUG that is commented out.

I think this is referring to pr_debug() calls. Those get called when you
add

#define DEBUG

to the file containing them. Otherwise they're optimized away.

-- 
Regards/Gruss,
Boris.